1. Field of the Invention
The present invention relates to the field of promoting regeneration of surface cartilage in damaged joints.
2. Description of the Background Art
In view of the large number of joint injuries, such as knee injuries, which take place yearly, a number of therapies have been developed in an effort to promote regeneration of damaged cartilage. Typical methods involve introduction of chondrocytes from an outside source into the damaged area to promote cartilage regeneration.
For example, in accordance with one method, a cartilage biopsy is surgically removed from the patient and sent to a laboratory, where the patient""s chondrocytes are isolated from the cartilage and the chondrocyte cells are reproduced in culture. Later, another surgery is performed on the patient wherein the damaged cartilage area to be treated is debrided back to expose healthy cartilage, leaving the subchondral bone plate intact. A periosteal patch is taken from the proximal medial tibia of the patient, and this periosteal patch is sutured to the rim of the healthy cartilage surrounding the area to be treated. The cultured chondrocytes reproduced from the cells previously taken from that patient then are injected under the patch into the defect, and the injury is allowed to heal.
U.S. Pat. No. 5,759,190 discloses another method, wherein a hemostatic barrier is placed proximal to the surface to be treated, chondrocytes in a matrix are placed upon the surface to be treated distal to the hemostatic barrier, and then the matrix is covered with a patch.
All of the above-described methods, in which the damaged area to be treated is covered with a patch, require multiple surgical procedures on the patient, wherein chondrocytes are removed from the patient, sent to a laboratory for culturing, and then the cultured chondrocytes are returned for implantation in to the patient in another surgical procedure.
There remains a need in the art for improved methods of promoting regeneration of surface cartilage in damaged joints so as to reduce the number of surgical procedures performed on a patient and eliminate the need for implanting cultured chondrocytes in the patient.
In accordance with the present invention, a method of promoting regeneration of surface cartilage of a joint includes the steps of forming a plurality of punctures in a subchondral plate of an area of the joint to be treated, covering the punctures and the area to be treated with a chondrocyte-free patch made of a sheet of collagen membrane material without adding chondrocytes to said area to be treated, fixing the patch over said area to be treated, and allowing said area to be treated to regenerate cartilage without adding chondrocytes to said area to be treated.